Designing and building complex systems, such as aircraft, space vehicles, marine vessels, marine platforms such as oil rigs, land vehicles such as automobiles and trucks, and the like, is a complex process that involves several disciplines. For example, typically several years of design, testing, analysis, and systems integration are performed before a complex system is put into operation. Furthermore, before the technician builds a component, subassembly, or assembly, an engineer analyzes a design for that component, subassembly, or assembly.
Engineers, typically, do not begin with a “clean sheet” nor is this approach useful. Most engineering is the result of extensive analysis of what has come before. Testing and analysis of materials inform the process of generating elements that are both structurally sound and adequate to the stresses imparted in use. Engineers learn by the repeated testing of materials, designs, structures, and configurations, even to the point of destruction. Indeed, most of the science of engineering in fields such as aviation stems from the wreckage of earlier designs.
The purpose of informed engineering is to change designs incrementally. It is inherent in the process of design that the design allows only a single variable within the design of a component, subassembly, or assembly under study to fluctuate, in order to track the effect of that variable. From these incremental changes in design and the changes in performance rendered by each, engineers abstract rules of design. Such rules might entail design constraints representing the minimum bending radius of structural aluminum or the safe load borne by a copper electrical conductor of a given diameter. Once abstracted, these rules dictate the farther variability in design of a component, subassembly, or assembly.
The domain of rules need not be restricted to matters relating only to safety or to performance. Indeed, there are rules that dictate the “look” of contemporary products. Any of the several offerings of the Volkswagen® line of the sixties and early seventies are immediately recognizable as Volkswagen®. Selectric® typewriters from the sixties to the late eighties also adhered to a particular profile that identified them as the products of IBM.
Rules exist stemming from every discipline are necessary to produce a product. Structural rules, design rules, functional dictates inform each step of the production of any modern product. There exists a need for these disciplines to reach a common starting point and from that point to quickly refine a design into a product.
The most complex of commercial products exist as the aggregation of mature technologies in a constellation of systems. Where manufacturers seek to introduce new technologies into the market place, they will mature the technology to the point that experience can assure the engineers of reliability. Thus the “rules set” for each discrete system is also matured.
An automobile, for instance, exists as the aggregation of fuel, power train, suspension, electrical, lighting, and hydraulic systems including brakes. Engineers know the specifications of a brake system necessary to safely stop a three-thousand-pound automobile. So too, they know the cooling capacity of the radiator necessary to cool a eight cylinder engine running under a particular load. Engineers know the rules of scale and application by the time a technology is mature enough for the marketplace.
Manufacturers have entire databases defining the individual components of the extant systems and the performance expected from each. Even at the sub-component level of process and material engineering, the manufacturers have studied extensively the materials they use, the machining, forging, or tooling that is possible or prudent with each of the materials, and the optimum application for each. Where the information relating to one application of a particular system is not complete, the resources certainly exist to complete it. These, too, are rules.
As discussed above, complete innovation is not desirable in commercial production. Once a manufacturer proposes a product to fill a niche in the manufacturer's product line, that niche defines the general dimensions and requirements of the product. Harkening again to the example of the automobile, a mid-size automobile might have a given weight and application. That weight and application will dictate a certain size of engine and attendant power train components, that size dictates the fuel delivery system necessary. Similarly, the mass of the proposed aggregate car will define the size of the braking system and suspension. Price points will dictate interior and trim packages. From such rules, there emerges a “blank” for the designers to manipulate into the new automotive product.
It should be possible to use computers to generate this “blank.” Even second and third generation “blanks” should be possible as Engineers learn, select and weigh more and more of the distinct parameters of the product through the study of the prior generation model. Each generation of blank should yield more definition and, given the interlocking nature of the rules, if a solution is possible, such increasingly refined “blanks” should continue to result. The models quickly cease to be blanks as they are refined. Thus, in the example, the parameter mid-sized sedan automobile with anti-lock brakes might define a nearly formed, absent cosmetic details, automobile.
Currently, to prototype a new product, is an extremely time-consuming process requiring much iteration. Engineers from each discipline will develop, from a set of requirements, a preliminary design document. This preliminary design document is, itself, the product of application of a series of known rules. From the preliminary design document, a designer configures a two-dimensional centerline preliminary design drawing. The preliminary design drawing represents definition of lines of a component, but the preliminary design drawing does not represent structure of the component. A designer takes the line definition from the preliminary design drawing and develops structural definition for the component. Structural definition comprises assigning properties and materials, and gages. Next, a designer generates surfaces for the component based on the structural definition. Surface generation is a very detailed, time-consuming process.
In surface generation, engineers impart the geometry and design information by using a computer assisted drafting (“CAD”) platform such as CATIA® or Unigraphics®. This process, too, is very time consuming. There are some economies available, especially as to where the configuration of particular elements are well-settled such as the general configuration of the empennage of an aircraft or the suspension of automobile. The production of such details as handles and latches still require a great number of placements. This situation exists in spite of the vast wealth of information that most manufacturers have as to a preferred or extant system for each operation or feature of the anticipated product. The CAD production of design drawings is laborious due to the hugely repetitious and principally rule-dictated decisions as to placement and deployment.
CAD drawings are not, themselves, complete representations of any but the most uniform surfaces. While the traditional views in three projections will well define a cube or a cylinder, the complex curvatures of most parts eludes definition by CAD. Many parts are designed with complex curves to maximize strength and to minimize weight and price of a component in a given application. These do not readily yield to definition in three projections. The best demonstration of this variability in surface description by two-dimensioned drawings in a traditional setting is the lofting of lines for the building of boat hulls. The stiffness of the battens used to connect well-defined lines while lofting a designer's plans might differentiate one boatyard's product from another. The resulting hulls might have very distinct performance characteristics when driven.
From the CAD-produced two-dimensional representations of the model, computers must then extract a surface geometry, exporting it to a modeling-computing environment such as UNIX. Because such generated surfaces typically include flaws or variability, the designers must clean up and make fair the surfaces. For example, the current state of the art uses meshing operations in commercially available modeling software. Soft software is notorious for introducing surface flaws. In most cases, where flaws in the surface generated cause the surface itself to be unworkable, designers must entirely recreate that surface. Again, much of the fairing of the surface relies upon a rule-dictated process. This laborious and time-consuming process precludes rapid design iteration.
Still further operation is necessary before the model is ripe for study. Once the process defines the surface, engineers must test the properties of the design. For this, the design is broken into finite elements. Each element consists of materials with properties that define the element's performance. The engineers evaluate the resulting whole for mass, balance, and structure. Each model can then be subject to static and dynamic testing, as desired or required. Evaluation often dictates changes necessary to meet design criteria. These changes trigger the reiteration of the process beginning at the generation of two-dimensioned CAD drawings.
This design process is inherently iterative. Engineers of the several disciplines will continue to refine the first design by testing or by application of rules through many, many iterations until the product of the process meets all of the objectives of the design. Finally, the design process must integrate all the finite elements into a model of a subassembly or assembly. When the process integrates the component, subassembly and assembly models into a single model, the engineers document the model, and the model is released. The above process can take thousands of labor hours and hundreds of manufacturing days, and represents just one single iteration of the design process.
Slicing has proven far easier than lofting. Where a three-dimensioned model exists, producing two-dimensioned drawings representative of the model is a relatively simple and extremely accurate process. The desired process, then, would begin with the generation of a study model of the desired product in three-dimensions.
If general dimensions and assumptions about a desired product could, through application of rules and integration of known design parameters, result in a reliably lofted and documented model of the desired product, the huge expense of one or several iterations of the design process would be greatly diminished or avoided. Further, if that model where readily accessible by the various software that test and analyze each of the components, the documentation result in far faster iterations of the design.
Thus, there is an unmet need in the art for a rapid, automated system and method for generating integrated data models that reduces analysis cycle time, and responds immediately to changes.